There has been recently proposed a pavement structure having a function of suppressing a surface temperature of a road, a sidewalk, or a roof of a building, in order to reduce the heat island effect. Patent Literature 1 proposes a permeable block and a permeable pavement each of which is capable of preventing rise in temperature of a pavement surface. FIG. 16 shows a structure of the permeable block according to Patent Literature 1. The permeable block includes a permeable body 51 that is made of a permeable material and has a porous shape, and a storage container 52 that is buried in the permeable body 51 and stores water. Rainwater or the like passes through the permeable body 51 and is then held in the storage container 52. The water thus held keeps the surface of the block wet to prevent rise in temperature.
Patent Literature 2 discloses a developed ground structure including a permeable layer, an impermeable layer surrounding the permeable layer, and a drain pipe that penetrates the impermeable layer and connects the permeable layer and an outer end of the permeable layer.